As far as I am aware people use synthol to do as samoth says, and stretch the fascia which surrounds the muscle. Once this fascia is stretched you are able to grow your muscle normally again, and the sysnthol is slowly dissipated into your body and (Presumably) flushed out as waste.

Most people who use synthol do so in this way, but some (Greg Valentino for example) take this to another level and try to make their whole body from synthol. The effect of that, as Im sure you have seen, is pretty horrible.

There is also greater dangers involved in synthol use. If you accidently get some AS into a vein you might get hot flushes, etc, but unless you stick LOTS directly into the vein you wont die. Synthol is differnt. Milos Sarcev nicked a vein injecting synthol and if his wife had not been there he would have died on the spot (Luckily for him she is a nurse or something)

Aside form this NO-ONE has performed studies to see what this stuff actually does to you when it "Dissipates" into your system. It might be flushed out, it might be clogging something up somehwhere. We will probably not find out until a post mortem is done on Greg Valentino!